US20210114711A1 - Composite spar for a wing structure - Google Patents
Composite spar for a wing structure Download PDFInfo
- Publication number
- US20210114711A1 US20210114711A1 US17/050,585 US201917050585A US2021114711A1 US 20210114711 A1 US20210114711 A1 US 20210114711A1 US 201917050585 A US201917050585 A US 201917050585A US 2021114711 A1 US2021114711 A1 US 2021114711A1
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- US
- United States
- Prior art keywords
- spar
- main body
- wing
- legs
- mandrel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C3/00—Wings
- B64C3/18—Spars; Ribs; Stringers
- B64C3/185—Spars
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/06—Fibrous reinforcements only
- B29C70/10—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres
- B29C70/16—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length
- B29C70/22—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length oriented in at least two directions forming a two dimensional structure
- B29C70/222—Fibrous reinforcements only characterised by the structure of fibrous reinforcements, e.g. hollow fibres using fibres of substantial or continuous length oriented in at least two directions forming a two dimensional structure the structure being shaped to form a three dimensional configuration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/40—Shaping or impregnating by compression not applied
- B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
- B29C70/46—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
- B29C70/48—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs and impregnating the reinforcements in the closed mould, e.g. resin transfer moulding [RTM], e.g. by vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D99/00—Subject matter not provided for in other groups of this subclass
- B29D99/0003—Producing profiled members, e.g. beams
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C23/00—Influencing air flow over aircraft surfaces, not otherwise provided for
- B64C23/06—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices
- B64C23/065—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips
- B64C23/069—Influencing air flow over aircraft surfaces, not otherwise provided for by generating vortices at the wing tips using one or more wing tip airfoil devices, e.g. winglets, splines, wing tip fences or raked wingtips
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
- B29L2031/3076—Aircrafts
- B29L2031/3085—Wings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/10—Drag reduction
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
Definitions
- This invention relates to a spar for a wing structure, such as a wingtip device, and particularly to such a spar that is made of composite material.
- a spar is a load-bearing structural element used in, for example, wings.
- Wing spars support the wing on the aircraft and, in flight, transmit lift generated by the wings to the fuselage of the aircraft.
- a spar may take many forms, but it has been found that box section spars provide good torsional stiffness. Therefore, a spar design having a box section along at least part of its length is preferred.
- spars have been made of metallic material. However, composite materials are becoming increasingly used because the resulting spar is generally lighter and stiffer than a conventional metallic spar.
- a typical composite spar is fabricated by a process known as Resin Transfer Moulding (RTM).
- RTM Resin Transfer Moulding
- This process consists of applying a fibre “layup” to the surface of a mandrel that corresponds to the interior surface of the entire length of the spar cavity.
- a die corresponding to the exterior surface of the spar is then applied and the mould assembly is closed, sealed and heated. Heated resin is injected to impregnate the fibre layup.
- the mould assembly may be placed under vacuum to assist the flow of resin.
- the mould assembly is then held at an elevated temperature in order to cure the resin.
- a problem which may be encountered with forming spars by means of RTM is that of removing the mandrel once the spar has been formed.
- the length of the mandrel makes it difficult to remove. Any variations in cross-sectional shape of the spar, or its contour, add to this difficulty.
- Certain desired configurations of spar are not possible to make by means of RTM because of the difficulty of removing the mandrel.
- the invention provides a composite spar comprising a main body and a pair of spaced apart legs, in which the spar follows a curved path which does not lie in a single plane.
- the space between the legs permits a spar to be manufactured on a mandrel assembly having any desired length and contour, as the space allows access to the mandrel assembly within the spar in order to ease its removal.
- the provision of access to the interior of the spar allows for spars having more complex contours to be manufactured.
- a spar constructed according to the invention may be made to support a structure, such as a wing or winglet, of a more complex shape than was achievable hitherto.
- a first end portion of the spar comprises the main body and is arranged to lie in a first plane; the other end portion of the spar comprises the free end portions of the legs, which are arranged to lie in a second plane.
- the spar further comprises a curved transition region between the planes.
- the main body is hollow.
- the hollow main body may be formed conventionally, as described above, but using a mandrel of much shorter length than was necessary hitherto, such that it is easier to remove.
- the legs are concave in section, with the openings facing each other.
- the legs together define an incomplete box section, which is structurally sturdy.
- Each leg may have a c-shaped cross section, which allows the spar to provide support to structural components, such as wing skins, that may be mounted to the upper and lower portions of the c-shape.
- the main body of the spar may be rectangular in cross section. This is the preferred configuration for providing torsional stiffness to the spar.
- the invention further provides a method of forming such a composite spar comprising the steps of: laying a fabric on a mandrel assembly; laying a die assembly over the fabric; injecting liquid resin into the fabric and curing the fabric by applying an elevated temperature—in other words, the process known as Resin Transfer Moulding.
- the mandrel assembly preferably includes a main body mandrel arranged to form the main body of the spar and which is slidably removable from the spar; a plurality of mandrel segments may also be provided and arranged to form the legs of the spar, each segment being slidably removable from the spar.
- a configuration of mandrel parts allows for relatively complex spar shapes to be made whilst still retaining the box section for the spar main body.
- the mandrel segments may be interlockable, with each segment arranged to abut the next, so as to provide a good support surface across the entire length of the spar during its manufacture.
- the composite spar may be incorporated in a wing tip device such as a winglet.
- a portion of the spar may be arranged to extend from the wing tip device so as to facilitate mounting of the wing tip device to the main body of a wing.
- the portion of the spar that extends from the wing tip device is preferably the main body portion.
- the main body of the spar is preferably arranged to support the winglet at its root, with the legs providing support along at least part of the span of the winglet.
- An aircraft wing structure including a spar constructed according to the present invention may comprise a wing main body and a wing tip device.
- Part of the spar, such as the main body, may protrude from the wing tip device and sit inside the wing main body.
- Such an arrangement provides a secure junction between the wing main body and the wing tip device.
- FIG. 1 is a perspective view of part of a spar constructed according to the invention
- FIG. 2 is a perspective view of mandrels used in forming the main body of the spar of FIG. 1 ;
- FIG. 3 shows the main body of the spar of FIG. 1 with the mandrels of FIG. 2 in situ;
- FIG. 4 is a perspective view of part of the spar of FIG. 1 , showing part of a mandrel used to form the legs of the spar;
- FIGS. 5 a and 5 b are perspective views of part of a wing structure incorporating the spar of FIG. 1 ;
- FIG. 6 is a perspective view of a complete wing structure incorporating the part of FIGS. 5 a and 5 b;
- FIG. 7 a is a front view of an aircraft incorporating the wing structure of FIG. 6 ;
- FIG. 7 b is a plan view of the aircraft of FIG. 6 a.
- the spar 1 comprises a main body 2 and a pair 3 , 4 of legs extending from the main body.
- the main body 2 has a hollow box structure that is rectangular in cross section. Such a structure provides good torsional stiffness.
- the main body 2 is elongated and extends in a straight line.
- the legs 3 , 4 are longer than the main body 2 and follow a curved path which does not lie in a single plane.
- the legs 3 , 4 extend further than is shown in this drawing.
- the legs 3 , 4 are spaced apart from each other and have c-shaped cross sections arranged so that the convex parts of the respective c-shapes face one another.
- the squared-off c-shaped sections together form an incomplete box section.
- the cross section of the leg 3 mirrors that of the leg 4 .
- the legs 3 , 4 provide support for any structure to which the spar 1 is attached and usefully transmit loads experienced by the structure to the main body 2 of the spar 1 .
- Each leg 3 , 4 comprises a wall 3 a , 4 a , a lower flange 3 b , 4 b and an upper flange 3 c , 4 c .
- the flanges 3 b , 4 b , 3 c , 4 c provide respective attachment surfaces so that the spar can be fixed to the structure to which it provides support, such as the skins of a wing, by, for example, adhesion or mechanical fastening.
- the main body 2 and legs 3 , 4 of the spar 1 are formed as one piece by an RTM method which will be outlined below.
- the mandrel assembly comprises main body mandrel 5 and a plurality of mandrel segments 6 , one of which is shown in FIG. 4 .
- the main body mandrel 5 is a solid rectangular piece for forming the main body 2 of the spar 1 .
- An end portion 5 a of the mandrel 5 is arranged to form the first portion of the legs 3 , 4 .
- the end 5 a has two protruding prongs 7 a , 7 b that define the inner contour of the legs 3 , 4 respectively.
- the first mandrel segment 6 is arranged to abut the end 5 a of the main body mandrel 5 . Subsequent mandrel segments are laid up to form the inner convex contours of the legs 3 , 4 of the spar in their entirety.
- the fibre layup comprises a unidirectional (UD) fabric 8 ( FIG. 3 ), which is one in which the majority of the fibres run in one direction only.
- UD unidirectional
- a so-called zero-degree fibre fabric is used, in which the fibres run along the length of the mandrel assembly.
- This arrangement of fibres gives good longitudinal strength of the finished spar.
- a small amount of fibre or other material may run in other directions, in order to strengthen the spar along its other axes. These fibres can also usefully hold the primary fibres in position.
- other materials could be used, such as woven mats, braided fibres or any other type of fibrous material known to the skilled person.
- a die assembly corresponding to the exterior surfaces of the spar is then applied.
- the entire assembly of mandrels, fabric and dies (collectively, the “mould assembly”) is then closed and sealed.
- Heated liquid resin matrix material is then injected into the mould assembly, and the resin infuses the fabric throughout the mould cavity.
- a vacuum is created within the tool to assist the flow of liquid resin.
- the mould assembly is then held at an elevated temperature in order to cure the resin. When the resin has solidified, the mould assembly is released, the exterior dies are removed and then the mandrels are extracted from the completed spar 1 .
- the main body mandrel 5 may be slid out of the main body 2 as its relatively short length allows for easy removal.
- the mandrel segments 6 are removed by sliding them along the spar 1 to the end of the legs 3 , 4 , or else by sliding them laterally into the gap between the legs, and then upwardly or downwardly out of the spar.
- the space between the legs 3 , 4 allows an operator easy access to the mandrel segments 6 to facilitate their removal, as is shown in FIG. 4 .
- the finished spar 1 is then ready for use as a support structure.
- FIGS. 5 a and 5 b show the completed spar 1 incorporated in part of a wing structure.
- the full extent of the legs 3 , 4 of the spar 1 are shown.
- the legs 3 , 4 comprise the majority of the overall length of the spar 1 .
- the main body 2 of the spar 1 comprises a first end portion, arranged to protrude from the wing structure and arranged to lie in a first plane (labelled A in FIG. 6 ).
- the main body 2 provides support and load transmission for the root of the wing structure.
- the legs 3 , 4 extend along a portion of the span of the wing structure.
- the legs 3 , 4 are of different lengths, and the leg 4 extends almost to the tip of the wing structure.
- the respective free end portions 3 d , 4 d of the legs 3 , 4 are arranged to lie in a second plane (labelled B in FIG. 6 ), with the spar curving along the transition region between the two planes.
- the wing structure comprises a winglet 9 .
- a winglet is a device that is attached to the tip of an aircraft wing in order to improve the aerodynamic performance of the aircraft in flight.
- the winglet 9 comprises a lower skin 10 , a plurality of reinforcing ribs 11 on the lower skin and the spar 1 arranged to extend along the span of the winglet 9 .
- the ribs 11 may be integrally formed with the lower skin 10 .
- a second spar 12 is also provided in order to give structural support to the front portion of the winglet 9 —that is to say, the portion adjacent the leading edge of the winglet in flight.
- the winglet 9 also includes an erosion shield 12 arranged to protect the leading edge.
- FIG. 6 shows a fully formed winglet 9 , which includes all of the features shown in FIGS. 5 a and 5 b , with the addition of an upper skin 13 forming the upper aerodynamic surface of the winglet.
- the winglet 9 is almost completely formed of composite material, with only a small number of parts, such as the erosion shield 12 , being formed of metallic material.
- the main body 2 of the spar 1 protrudes from the assembled winglet 9 and provides the main attachment point of the winglet to the main body of a wing.
- a winglet with a smooth curve such as that shown in the drawings, is known as a blended winglet.
- Blended winglets are intended to reduce interference drag at the junction between the main body of the wing and the winglet.
- FIGS. 7 a and 7 b show such a winglet incorporated in an aircraft.
- the aircraft indicated generally by the reference numeral 13 , comprises a fuselage 14 and a pair 15 , 16 of wings.
- Each wing comprises a wing main body 15 a , 16 a and a winglet 9 .
- the wing main bodies 15 a , 16 a produce lift for the aircraft and also house fuel tanks (not visible in these drawings).
- the wing main bodies may also incorporate leading edge devices, such as slats, and trailing edge devices such as flaps.
- Each winglet 9 is attached to the tip of its respective wing main body 15 a , 16 a , with the protruding part of the main body 2 of the spar 1 being located inside the interior of the wing main body.
- Each winglet 9 is arranged to provide an upwardly curving wing tip. In flight, the winglets 9 increase the lift generated at the wingtip by smoothing the airflow across the upper wing near the tip. The winglets also reduce the lift-induced drag caused by wingtip vortices, improving lift-to-drag ratio.
- the main body of the spar 1 need not be completely hollow: internal webs may be employed to provide further stiffness, or even a solid body may be used.
- the cross section of the main body 2 of the spar 1 need not be rectangular: it may be square, rounded or have another polygonal shape.
- the legs 3 , 4 may be parallel to each other or they may be arranged to splay outwardly from the main body 2 of the spar 1 .
- the legs 3 , 4 of the spar shown in this embodiment have different lengths; naturally, the spar can be made to have legs of the same length.
- the legs 3 , 4 are arranged to conform to the contours of the structure to which the spar gives support.
- the legs 3 , 4 may have other shapes of cross-section, provided that they are designed with sufficient space for moving the mandrel parts out of engagement with the finished spar.
- the legs 3 , 4 may be arranged to have different respective cross sections. More legs may be provided to extend from the main body, if required.
- the spar of the present invention has been described in the context of providing a support structure for a winglet arranged at the tip of the wing; however, the spar may be used on the main body of a wing, with the main body 2 of the spar 1 delivering a mechanical and structural link between the wing and the fuselage of the aircraft.
- the spar of the present invention may alternatively be used in turbine blades, rotary wings, propellers, fan blades or other structures requiring internal structural support. Further variations will be apparent to the person skilled in the art.
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Abstract
Description
- This invention relates to a spar for a wing structure, such as a wingtip device, and particularly to such a spar that is made of composite material.
- A spar is a load-bearing structural element used in, for example, wings. Wing spars support the wing on the aircraft and, in flight, transmit lift generated by the wings to the fuselage of the aircraft. A spar may take many forms, but it has been found that box section spars provide good torsional stiffness. Therefore, a spar design having a box section along at least part of its length is preferred. Traditionally, spars have been made of metallic material. However, composite materials are becoming increasingly used because the resulting spar is generally lighter and stiffer than a conventional metallic spar.
- A typical composite spar is fabricated by a process known as Resin Transfer Moulding (RTM). This process consists of applying a fibre “layup” to the surface of a mandrel that corresponds to the interior surface of the entire length of the spar cavity. A die corresponding to the exterior surface of the spar is then applied and the mould assembly is closed, sealed and heated. Heated resin is injected to impregnate the fibre layup. The mould assembly may be placed under vacuum to assist the flow of resin. The mould assembly is then held at an elevated temperature in order to cure the resin.
- A problem which may be encountered with forming spars by means of RTM is that of removing the mandrel once the spar has been formed. The length of the mandrel makes it difficult to remove. Any variations in cross-sectional shape of the spar, or its contour, add to this difficulty. Certain desired configurations of spar are not possible to make by means of RTM because of the difficulty of removing the mandrel.
- The invention provides a composite spar comprising a main body and a pair of spaced apart legs, in which the spar follows a curved path which does not lie in a single plane. The space between the legs permits a spar to be manufactured on a mandrel assembly having any desired length and contour, as the space allows access to the mandrel assembly within the spar in order to ease its removal. The provision of access to the interior of the spar allows for spars having more complex contours to be manufactured. Thus, a spar constructed according to the invention may be made to support a structure, such as a wing or winglet, of a more complex shape than was achievable hitherto.
- Preferably, a first end portion of the spar comprises the main body and is arranged to lie in a first plane; the other end portion of the spar comprises the free end portions of the legs, which are arranged to lie in a second plane. The spar further comprises a curved transition region between the planes.
- Advantageously, the main body is hollow. The hollow main body may be formed conventionally, as described above, but using a mandrel of much shorter length than was necessary hitherto, such that it is easier to remove.
- Preferably, the legs are concave in section, with the openings facing each other. Thus, the legs together define an incomplete box section, which is structurally sturdy.
- Each leg may have a c-shaped cross section, which allows the spar to provide support to structural components, such as wing skins, that may be mounted to the upper and lower portions of the c-shape.
- The main body of the spar may be rectangular in cross section. This is the preferred configuration for providing torsional stiffness to the spar.
- The invention further provides a method of forming such a composite spar comprising the steps of: laying a fabric on a mandrel assembly; laying a die assembly over the fabric; injecting liquid resin into the fabric and curing the fabric by applying an elevated temperature—in other words, the process known as Resin Transfer Moulding.
- The mandrel assembly preferably includes a main body mandrel arranged to form the main body of the spar and which is slidably removable from the spar; a plurality of mandrel segments may also be provided and arranged to form the legs of the spar, each segment being slidably removable from the spar. Such a configuration of mandrel parts allows for relatively complex spar shapes to be made whilst still retaining the box section for the spar main body.
- The mandrel segments may be interlockable, with each segment arranged to abut the next, so as to provide a good support surface across the entire length of the spar during its manufacture.
- The composite spar may be incorporated in a wing tip device such as a winglet. A portion of the spar may be arranged to extend from the wing tip device so as to facilitate mounting of the wing tip device to the main body of a wing. The portion of the spar that extends from the wing tip device is preferably the main body portion.
- The main body of the spar is preferably arranged to support the winglet at its root, with the legs providing support along at least part of the span of the winglet.
- An aircraft wing structure including a spar constructed according to the present invention may comprise a wing main body and a wing tip device. Part of the spar, such as the main body, may protrude from the wing tip device and sit inside the wing main body. Such an arrangement provides a secure junction between the wing main body and the wing tip device.
- The invention will now be described, by way of example, with reference to the accompanying drawings in which:
-
FIG. 1 is a perspective view of part of a spar constructed according to the invention; -
FIG. 2 is a perspective view of mandrels used in forming the main body of the spar ofFIG. 1 ; -
FIG. 3 shows the main body of the spar ofFIG. 1 with the mandrels ofFIG. 2 in situ; -
FIG. 4 is a perspective view of part of the spar ofFIG. 1 , showing part of a mandrel used to form the legs of the spar; -
FIGS. 5a and 5b are perspective views of part of a wing structure incorporating the spar ofFIG. 1 ; -
FIG. 6 is a perspective view of a complete wing structure incorporating the part ofFIGS. 5a and 5 b; -
FIG. 7a is a front view of an aircraft incorporating the wing structure ofFIG. 6 ; and -
FIG. 7b is a plan view of the aircraft ofFIG. 6 a. - With reference to
FIG. 1 , part of a spar constructed according to the invention is indicated generally by thereference numeral 1. Thespar 1 comprises amain body 2 and apair main body 2 has a hollow box structure that is rectangular in cross section. Such a structure provides good torsional stiffness. Themain body 2 is elongated and extends in a straight line. Thelegs main body 2 and follow a curved path which does not lie in a single plane. Thelegs legs leg 3 mirrors that of theleg 4. Thelegs spar 1 is attached and usefully transmit loads experienced by the structure to themain body 2 of thespar 1. Eachleg wall lower flange upper flange flanges main body 2 andlegs spar 1 are formed as one piece by an RTM method which will be outlined below. - Firstly, the fibre layup is applied to the surface of a metallic mandrel assembly, part of which is shown in
FIG. 2 . The mandrel assembly comprisesmain body mandrel 5 and a plurality ofmandrel segments 6, one of which is shown inFIG. 4 . Themain body mandrel 5 is a solid rectangular piece for forming themain body 2 of thespar 1. Anend portion 5 a of themandrel 5 is arranged to form the first portion of thelegs end 5 a has two protrudingprongs legs first mandrel segment 6 is arranged to abut theend 5 a of themain body mandrel 5. Subsequent mandrel segments are laid up to form the inner convex contours of thelegs - The fibre layup comprises a unidirectional (UD) fabric 8 (
FIG. 3 ), which is one in which the majority of the fibres run in one direction only. In this embodiment, a so-called zero-degree fibre fabric is used, in which the fibres run along the length of the mandrel assembly. This arrangement of fibres gives good longitudinal strength of the finished spar. A small amount of fibre or other material may run in other directions, in order to strengthen the spar along its other axes. These fibres can also usefully hold the primary fibres in position. Of course, other materials could be used, such as woven mats, braided fibres or any other type of fibrous material known to the skilled person. - A die assembly corresponding to the exterior surfaces of the spar is then applied. The entire assembly of mandrels, fabric and dies (collectively, the “mould assembly”) is then closed and sealed. Heated liquid resin matrix material is then injected into the mould assembly, and the resin infuses the fabric throughout the mould cavity. A vacuum is created within the tool to assist the flow of liquid resin. The mould assembly is then held at an elevated temperature in order to cure the resin. When the resin has solidified, the mould assembly is released, the exterior dies are removed and then the mandrels are extracted from the completed
spar 1. - During the demoulding process, the
main body mandrel 5 may be slid out of themain body 2 as its relatively short length allows for easy removal. Themandrel segments 6 are removed by sliding them along thespar 1 to the end of thelegs legs mandrel segments 6 to facilitate their removal, as is shown inFIG. 4 . Thefinished spar 1 is then ready for use as a support structure. -
FIGS. 5a and 5b show the completedspar 1 incorporated in part of a wing structure. In this drawing, the full extent of thelegs spar 1 are shown. As can be seen, thelegs spar 1. Themain body 2 of thespar 1 comprises a first end portion, arranged to protrude from the wing structure and arranged to lie in a first plane (labelled A inFIG. 6 ). Themain body 2 provides support and load transmission for the root of the wing structure. Thelegs legs leg 4 extends almost to the tip of the wing structure. The respectivefree end portions legs FIG. 6 ), with the spar curving along the transition region between the two planes. - In this embodiment, the wing structure comprises a
winglet 9. A winglet is a device that is attached to the tip of an aircraft wing in order to improve the aerodynamic performance of the aircraft in flight. Thewinglet 9 comprises alower skin 10, a plurality of reinforcingribs 11 on the lower skin and thespar 1 arranged to extend along the span of thewinglet 9. Theribs 11 may be integrally formed with thelower skin 10. Asecond spar 12 is also provided in order to give structural support to the front portion of thewinglet 9—that is to say, the portion adjacent the leading edge of the winglet in flight. Thewinglet 9 also includes anerosion shield 12 arranged to protect the leading edge. -
FIG. 6 shows a fully formedwinglet 9, which includes all of the features shown inFIGS. 5a and 5b , with the addition of anupper skin 13 forming the upper aerodynamic surface of the winglet. Thewinglet 9 is almost completely formed of composite material, with only a small number of parts, such as theerosion shield 12, being formed of metallic material. Themain body 2 of thespar 1 protrudes from the assembledwinglet 9 and provides the main attachment point of the winglet to the main body of a wing. - A winglet with a smooth curve, such as that shown in the drawings, is known as a blended winglet. Blended winglets are intended to reduce interference drag at the junction between the main body of the wing and the winglet.
FIGS. 7a and 7b show such a winglet incorporated in an aircraft. The aircraft, indicated generally by thereference numeral 13, comprises afuselage 14 and apair winglet 9. The wing main bodies 15 a, 16 a produce lift for the aircraft and also house fuel tanks (not visible in these drawings). The wing main bodies may also incorporate leading edge devices, such as slats, and trailing edge devices such as flaps. Eachwinglet 9 is attached to the tip of its respective wing main body 15 a, 16 a, with the protruding part of themain body 2 of thespar 1 being located inside the interior of the wing main body. Eachwinglet 9 is arranged to provide an upwardly curving wing tip. In flight, thewinglets 9 increase the lift generated at the wingtip by smoothing the airflow across the upper wing near the tip. The winglets also reduce the lift-induced drag caused by wingtip vortices, improving lift-to-drag ratio. - Variations may be made without departing from the scope of the invention. For example, the main body of the
spar 1 need not be completely hollow: internal webs may be employed to provide further stiffness, or even a solid body may be used. The cross section of themain body 2 of thespar 1 need not be rectangular: it may be square, rounded or have another polygonal shape. - The
legs main body 2 of thespar 1. Thelegs legs legs legs - The spar of the present invention has been described in the context of providing a support structure for a winglet arranged at the tip of the wing; however, the spar may be used on the main body of a wing, with the
main body 2 of thespar 1 delivering a mechanical and structural link between the wing and the fuselage of the aircraft. The spar of the present invention may alternatively be used in turbine blades, rotary wings, propellers, fan blades or other structures requiring internal structural support. Further variations will be apparent to the person skilled in the art.
Claims (19)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1806888.2A GB2573285A (en) | 2018-04-27 | 2018-04-27 | Composite spar for a wing structure |
GB1806888.2 | 2018-04-27 | ||
PCT/EP2019/060703 WO2019207089A1 (en) | 2018-04-27 | 2019-04-26 | Composite spar for a wing structure |
Publications (1)
Publication Number | Publication Date |
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US20210114711A1 true US20210114711A1 (en) | 2021-04-22 |
Family
ID=62494983
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/050,585 Abandoned US20210114711A1 (en) | 2018-04-27 | 2019-04-26 | Composite spar for a wing structure |
Country Status (3)
Country | Link |
---|---|
US (1) | US20210114711A1 (en) |
GB (1) | GB2573285A (en) |
WO (1) | WO2019207089A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20230159154A1 (en) * | 2021-11-24 | 2023-05-25 | Airbus Operations (S.A.S.) | Flexible pillar for a flexible frame of a variable geometry flight control surface |
US20230373610A1 (en) * | 2020-09-29 | 2023-11-23 | Airbus Operations Limited | A cover panel |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2597522A (en) | 2020-07-27 | 2022-02-02 | Airbus Operations Ltd | Winglet and winglet cover assembly |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020195524A1 (en) * | 1999-07-19 | 2002-12-26 | Fuji Jukogyo Kabushiki Kaisha | Method of fabricating a wing of composite material |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7165945B2 (en) * | 2003-08-22 | 2007-01-23 | Sikorsky Aircraft Corporation | Braided spar for a rotor blade and method of manufacture thereof |
FR2962175B1 (en) * | 2010-07-02 | 2012-08-10 | Snecma | AUBE A LONGERON INTEGRATED COMPOSITE |
GB201307066D0 (en) * | 2013-04-18 | 2013-05-29 | Airbus Operations Ltd | Winglet and braided composite spar |
US9452825B2 (en) * | 2013-04-19 | 2016-09-27 | The Boeing Company | Winglet attach fitting for attaching a split winglet to a wing |
GB2544810A (en) * | 2015-11-30 | 2017-05-31 | Airbus Operations Ltd | Swing wing Tip |
GB2550403A (en) * | 2016-05-19 | 2017-11-22 | Airbus Operations Ltd | Aerofoil body with integral curved spar-cover |
-
2018
- 2018-04-27 GB GB1806888.2A patent/GB2573285A/en not_active Withdrawn
-
2019
- 2019-04-26 WO PCT/EP2019/060703 patent/WO2019207089A1/en active Application Filing
- 2019-04-26 US US17/050,585 patent/US20210114711A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20020195524A1 (en) * | 1999-07-19 | 2002-12-26 | Fuji Jukogyo Kabushiki Kaisha | Method of fabricating a wing of composite material |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20230373610A1 (en) * | 2020-09-29 | 2023-11-23 | Airbus Operations Limited | A cover panel |
US20230159154A1 (en) * | 2021-11-24 | 2023-05-25 | Airbus Operations (S.A.S.) | Flexible pillar for a flexible frame of a variable geometry flight control surface |
US12054257B2 (en) * | 2021-11-24 | 2024-08-06 | Airbus Operations (S.A.S.) | Flexible pillar for a flexible frame of a variable geometry flight control surface |
Also Published As
Publication number | Publication date |
---|---|
WO2019207089A1 (en) | 2019-10-31 |
GB201806888D0 (en) | 2018-06-13 |
GB2573285A (en) | 2019-11-06 |
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